Aclidinium bromide is 3(R)-(2-hydroxy-2,2-dithien-2-ylacetoxy)-1-(3-phenoxypropyl)-1-azoniabicyclo[2.2.2]octane bromide, described in, e.g., WO 0104118. Although this compound is known to be a long-acting anticholinergic useful in the treatment of respiratory diseases, the optimal dosage is not disclosed.